Choke and throttle connection



R. G. HE-NNEMANN I 2,426,272

CHOKE AND THROTTLE CONNECTION Filed Aug. 14, 1944 INVENTOR. RAYMOND G. HENNEMANN Z zw Patented Aug. 26, 1947 CHOKE AND THROTTLE CONNECTION Raymond'G. Hennemann, St. Louis County, Mo., assignor to Carter Carburetor Corporation, St. Louis, Mo a corporation of Delaware Application August 14, 1944, Serial No; 549,454

1 Claim.

This invention relates to linkage devices particularly adapted for interconnecting the choke and throttle valves of an automotive carburetor. Such carburetors, especially of the automatic choke type, ordinarily have interconnection structure between the choke and throttle valves for limiting the closing movement of the throttle valve to the fast idle position, when the choke valve is closed, and also for causing partial opening of the choke valve, when the throttle is fully opened, to permit sweeping out or unloading of excess fuel which may collect in the engine manifold. One form of automatic choke and interconnection mechanism is illustrated and claimed in a copending application of George M, Bicknell, Serial No. 464,643, filed November 5, 1942, now Patent No. 2,402,361, issued June 18, 1946.

The object of the present invention is to provide simplified means for adjusting the length of the linkage without disconnecting the linkage from the choke and throttle parts operated thereby.

This object and other more detailed objects hereafter appearing are obtained substantially by the structure illustrated in the accompanying drawings in which Fig. 1 is a side view, partly sectioned, illustrating an automotive carburetor embodying the invention.

Fig. 2 is a view of the linkage and controlling parts only in a different position.

Fig. 3 is a view of a detail of the linkage taken at 90 to Fig. 2.

Fig. 4 is an enlarged, detail, longitudinal section taken on line 44 of Fig. 3.

Fig. 5 is an enlarged transverse section taken on line -55 of Fig. 2, butbe'fore crimping of the jaw elements.

The carburetor shown has a downdraft mixture barrel 5, the upper or air inlet horn portion of which is controlled by a butterfly choke valve 'l. The lower end of the barrel is flanged, as at 8, for attachment to the engine intake manifold (not shown) and is controlled by a butterfly throttle valve 9. An automatic choke housing It mounted on the outside of the air inlet horn encloses a cam I2 rigidly secured to the end of choke shaft I3. A bell crank it is pivoted at l5 eccentrically with respect to the choke shaft. Bell crank l lhas an arm H5 which cooperates with a pin l'l projecting from cam I2 and has a second, longer arm l8 for cooperation with the interconnection linkage to be described. Arm l8 also has an inward lug 19 for engaging cam 12 to limit the closing movement of the throttle,

as hereinafter described. A choke controlling thermostat (not shown) and a suction piston in cylinder H are also located in housing Hi, as disclosed in the above-mentioned Bicknell application.

A double arm operating lever 20 is rigidly secured to throttle shaft 2! and has holes 22 andZS for attachment of the usual accelerator linkage which extends to the drivers compartment.

.The'interconnection linkage comprises a lower end member 25 having a bent over, lower end attached to the throttlelever. The other end of member 25' is threadedly received in an adjusting sleeve 26 having an annular groove 21 in the upper extremity thereof. The sides of this groove are inwardly inclined so that the groove is frustoconical in section, as best shown in Fig. 4. A lock nut 28 is also threaded on member 25.

The upper end member 29 is formed. as a sheet metal stamping and is guided for longitudinal movement only by a slot 30 formed in an enlargement '3! below housing H). Member 29 is cut out,

as at 32, to form a shoulder 33 and a finger 34 which cooperate with bell crank arm [8. End member 29 and adjusting sleeve 26 are connected by an angular element 35 which has a transverse, split eye part 36 snugly but rotatably receiving groove 21 in the adjusting sleeve. The upright part of element 35 is swivelled to the lower end of end member 29 about a transverse pin pivot 37. In assembling member 29 and element 35, the flattened head of pivot pin 31 is turned sideways and inserted in a horizontal slot 38 and the pin is then turned A coiled spring 39 is compressed between the head of pin 31 and end member .29 to prevent looseness, rattling, and wear at this point.

Connecting element 35 is initially formed as shown in Fig. 5. In assembly, member 26 is inserted in the eye and the ends on jaws thereof are then squeezed together so as to closely fit against and about the inclined edges of the groove 21. The resulting split eye may be tightened at any time in order to take out any looseness which develops in the joint.

The automatic choke mechanism operates as follows:

When the throttle is moved toward closed position, linkage end member 29 is lifted, as shown in Fig. 1, bringing shoulder 33 into engagement with bell crank arm 18, rotating the bell crank clockwise until inward, lug l9 engages cam I2. If the choke valve is opened, as in Fig. 1, lug I9 will engage a relatively low point on the cam to permit closing of the throttle to its normally idling position. However, if the choke is closed, or partially open, as it will be during cold starting and warm-up, cam 1.2 will be rotated to bring a relatively higher point thereon into engagement with lug l9 and the closing of the throttle will be limited to a fast idle position. In case of loading of the engine with excess fuel during starting, the chok may be opened, as shown in Fig. 2, by wide open movement of the throttle valve, which brings finger 34 into engagement with arm I8 of bell crank 14, rotating the bell crank counter-clockwise to bring arm l'6 thereof against pin I l on cam 12 and rotate the cam and choke clockwise or in th opening direction.

The interrelated movementsof the choke and throttle, as described, must be carefully adjusted. Such adjustments may be easily effected by loosening of lock nut 28 and rotation of adjusting sleeve 26 without the necessity of disassociating either of end members 25 or 29 from their cooperating throttle and choke parts. When the adjustment is obtained, the adjusting sleeve is locked in position by the lock nut.

The invention may be modified in various respects as will occur to those skilled in the art and the exclusive use of all modifications as come within the scope of the appended claim is contemplated.

I claim:

In a carburetor having choke and throttle valves, pivoted control members movable respectively with said valves, said members being substantially disaligned both as to their axis and their planes of operation, and interconnection linkage between said members comprising first and second end links, said first end link being directly engageable by said choke control member and being guided for axial, rectilinear movements only, and the other end link being pivotally connected to said throttle control member, a first intermediate part swiveled at its upper end about a transverse axis to said rectilinearly movable link, and a second intermediate part having an adjustable pivotal joint connection with said first intermediate part about a longitudinal axis and threadedly connected to said second end link whereby said linkage will adjust itself without binding disalignment of said control members and the length thereof may be adjusted by rotation of said second intermediate part without disassembly of said linkage from said control members.

RAYMOND G. HENNEMANN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,968,870 Beals Aug. 7, 1934 993,210 Weiss May 23, 1911 2,198,676 Mallory Apr. 30, 1940 1,784,481 Bicknell Dec. 9, 1930 2,160,410 Blattner May 30, 1939 

